diff --git a/crates/karva/tests/it/basic.rs b/crates/karva/tests/it/basic.rs
index 62a4be47..94acd3a0 100644
--- a/crates/karva/tests/it/basic.rs
+++ b/crates/karva/tests/it/basic.rs
@@ -1446,73 +1446,6 @@ def test_pass():
     ");
 }
 
-#[test]
-fn test_fail_fast() {
-    let context = TestContext::with_file(
-        "test.py",
-        r"
-def test_1():
-    assert True
-
-def test_2():
-    assert False
-
-def test_3():
-    assert True
-        ",
-    );
-
-    let output = context
-        .command_no_parallel()
-        .arg("--fail-fast")
-        .output()
-        .expect("failed to run");
-    let stdout = String::from_utf8_lossy(&output.stdout);
-    assert!(!output.status.success());
-    assert!(
-        stdout.contains("PASS") && stdout.contains("test::test_1"),
-        "first test should pass"
-    );
-    assert!(
-        stdout.contains("FAIL") && stdout.contains("test::test_2"),
-        "second test should fail"
-    );
-    assert!(
-        !stdout.contains("test::test_3"),
-        "third test should not run due to --fail-fast"
-    );
-}
-
-#[test]
-fn test_fail_fast_across_modules() {
-    let context = TestContext::with_files([
-        (
-            "test_a.py",
-            r"
-def test_a_fail():
-    assert False
-            ",
-        ),
-        (
-            "test_b.py",
-            r"
-def test_b_pass():
-    assert True
-            ",
-        ),
-    ]);
-
-    let output = context
-        .command_no_parallel()
-        .arg("--fail-fast")
-        .arg("-q")
-        .output()
-        .expect("failed to run");
-    assert!(!output.status.success());
-    let stdout = String::from_utf8_lossy(&output.stdout);
-    assert!(stdout.contains("failed"), "should report failure");
-}
-
 #[test]
 fn test_dry_run_nested_packages() {
     let context = TestContext::with_files([
diff --git a/crates/karva/tests/it/last_failed.rs b/crates/karva/tests/it/last_failed.rs
index fabc92b3..39fbf8be 100644
--- a/crates/karva/tests/it/last_failed.rs
+++ b/crates/karva/tests/it/last_failed.rs
@@ -172,6 +172,47 @@ def test_fail_b(): assert False
     ");
 }
 
+/// Combining `--last-failed` with `-E` should further narrow the rerun set
+/// to only previously-failed tests that also match the filter expression.
+#[test]
+fn last_failed_with_filter_narrows_rerun_set() {
+    let context = TestContext::with_files([
+        (
+            "test_a.py",
+            "
+def test_pass_a(): pass
+def test_fail_a(): assert False
+            ",
+        ),
+        (
+            "test_b.py",
+            "
+def test_pass_b(): pass
+def test_fail_b(): assert False
+            ",
+        ),
+    ]);
+
+    context.command_no_parallel().output().unwrap();
+
+    assert_cmd_snapshot!(
+        context
+            .command_no_parallel()
+            .arg("--last-failed")
+            .args(["-E", "test(~fail_a)"])
+            .arg("-q"),
+        @"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    ────────────
+         Summary [TIME] 2 tests run: 0 passed, 1 failed, 1 skipped
+
+    ----- stderr -----
+    ",
+    );
+}
+
 #[test]
 fn last_failed_fix_then_rerun() {
     let context = TestContext::with_file(
diff --git a/crates/karva_python_semantic/src/function_kind.rs b/crates/karva_python_semantic/src/function_kind.rs
index 2cb6faf5..6d8c3ccd 100644
--- a/crates/karva_python_semantic/src/function_kind.rs
+++ b/crates/karva_python_semantic/src/function_kind.rs
@@ -16,18 +16,3 @@ impl FunctionKind {
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_capitalised_test() {
-        assert_eq!(FunctionKind::Test.capitalised(), "Test");
-    }
-
-    #[test]
-    fn test_capitalised_fixture() {
-        assert_eq!(FunctionKind::Fixture.capitalised(), "Fixture");
-    }
-}
diff --git a/crates/karva_runner/src/orchestration.rs b/crates/karva_runner/src/orchestration.rs
index b3922d77..80d57a45 100644
--- a/crates/karva_runner/src/orchestration.rs
+++ b/crates/karva_runner/src/orchestration.rs
@@ -436,50 +436,3 @@ fn inner_cli_args(settings: &ProjectSettings, args: &SubTestCommand) -> Vec<Stri
 
     cli_args.iter().map(ToString::to_string).collect()
 }
-
-#[cfg(test)]
-mod tests {
-    use super::MIN_TESTS_PER_WORKER;
-
-    /// Helper to compute the effective worker count using the same formula as `run_parallel_tests`.
-    fn effective_workers(num_workers: usize, total_tests: usize) -> usize {
-        let max_useful = total_tests.div_ceil(MIN_TESTS_PER_WORKER).max(1);
-        num_workers.min(max_useful)
-    }
-
-    #[test]
-    fn test_workers_capped_for_small_test_count() {
-        // 9 tests / 5 per worker = ceil(1.8) = 2 workers
-        assert_eq!(effective_workers(8, 9), 2);
-    }
-
-    #[test]
-    fn test_workers_capped_for_medium_test_count() {
-        // 25 tests / 5 per worker = ceil(5) = 5 workers
-        assert_eq!(effective_workers(8, 25), 5);
-    }
-
-    #[test]
-    fn test_workers_unchanged_when_test_count_is_high() {
-        // 100 tests / 5 per worker = ceil(20) = 20, but only 8 workers requested
-        assert_eq!(effective_workers(8, 100), 8);
-    }
-
-    #[test]
-    fn test_at_least_one_worker_with_zero_tests() {
-        // 0 tests should still yield at least 1 worker
-        assert_eq!(effective_workers(8, 0), 1);
-    }
-
-    #[test]
-    fn test_workers_capped_for_very_few_tests() {
-        // 3 tests / 5 per worker = ceil(0.6) = 1 worker
-        assert_eq!(effective_workers(8, 3), 1);
-    }
-
-    #[test]
-    fn test_workers_exact_multiple() {
-        // 40 tests / 5 per worker = 8 workers exactly
-        assert_eq!(effective_workers(8, 40), 8);
-    }
-}